Authors:

Z. Helming(Rensselaer Polytech Inst)

D. Zagorevski(Rensselaer Polytech Inst)

C.Y. Ryu(Rensselaer Polytech Inst)

Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock
copolymers are a group of commercial macromolecular amphiphilic surfactants
that have been widely studied for their applications in polymer-based
nanotechnology and drug-delivery. It has been well-established that the
synthesis of commercial Pluronic triblocks results in low molecular weight
``impurities,'' which are generally disregarded in the applications and
study of these polymers. These species have been shown to have significant
effects on the rheological properties of the material, as well as altering
the supramolecular ``micellar'' structures for which the polymers are most
often used. We have isolated the impurities from the bulk Pluronic triblock
using Interaction Chromatography (IC) techniques, and subjected them to
analysis by H$_{1}$ NMR and MALDI (Matrix-Assisted Laser Desorption
Ionization) Mass Spectrometry to identify relative block composition and
molecular weight information. We report significant evidence of at least two
polymeric components: a low-molecular-weight homopolymer of poly(ethylene
oxide) and a ``blocky'' copolymer of both poly(ethylene oxide) and
poly(propylene oxide). This has significant implications, not only for the
applied usage of Pluronic triblock copolymers, but for the general
scientific acceptance of the impurities and their effects on Pluronic
micelle and hydrogel formation.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2014.MAR.P1.217